Taken from Astra Owners Club (with permission):

Oddjob said:

A mate at work has 2 Astra coupes, ones a 2.2 with a little bit of Irmy kit one and the others a 1.8. He's not really mechanically minded and always asks for my advise when something concerns him.

He normally uses the 2.2 whilst his daughter uses the 1.8, the other day he came up and said his car was running in limp home mode, sounded rough and misfiring. He'd removed the coil pack to find the plugs submerged in water, which was causing the misfire. He thought a hose had burst and flooded the head cavity, however he could find no pipes leaking. There was no oil in the water and a compression test didn't point to a head gasket.

However he took it to a Vx mechanic he knows who's found that the head has corroded in a small area and is allowing antifreeze to flow into the spark plug area.

Here's where it gets interesting, my mate has been topping his header tank up with normal antifreeze, not the Vx stuff or the special silicate anti freeze the 2.2 should use, this has mixed with his normal antifreeze and resulted in it eating it's way out of the head.

So any 2.2 owners should be warned this is a BIG no no, he's trying to fix it by using some stuff you pour into the head and run for 4 hours, after that his mate has recommended he get shut, which is a shame as he really likes the car.

Anyone got a spare head for a 2.2? if he can replace it cheaply enough he'll keep the car.

Source: http://www.astraownersclub.com/vb/showt ... p?t=116468